To amp up the effectiveness of its ads, Facebook in recent months has begun allowing marketers to target ads at users based on the email address and phone number they list on their profiles, or based on their surfing habits on other sites.

It has also started selling ads that follow Facebook members beyond the confines of the social network.

Along with executive turmoil — including the upcoming stepping back of tech lead Eric Feng and Shawn Fanning, Parker’s Napster co-founder, who was the CEO and driving force behind Airtime while Parker was focused on Spotify last year — there has also been a very weak launch in getting Airtime off the ground.

Mr. Zuckerberg and Mr. Medvedev talked about Facebook’s role in politics, though only jokingly in reference to its importance in the American presidential campaign, according to Mr. Medvedev’s press office.

They also discussed copyright rules and high-tech business. Mr. Zuckerberg gave the Russian leader a T-shirt; the meeting lasted about 20 minutes.

I did encounter some puzzling aspects of Windows 8. The bimodal user experience can introduce confusion, especially when two versions of the same application – such as Internet Explorer – can be opened and run simultaneously. Files can also be opened in either of the two available modes.

Fadell’s homage to Apple and Jobs goes beyond theatrics. The new Nest, which replaces the old Nest and still sells for $249, is thinner (“20% thinner,” Fadell says), one piece of stainless steel rather than two, has more connectors than the first version, and even has a neater back side. This last bit is a nice nod to the Jobs obsession with the inside of the early Macintosh, the part consumers wouldn’t see. The back of a Nest goes up against the wall. Get it?

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